function _scrollTop(  time ){

$(document.body).animate({scrollTop:0}, time );

}

function _scroll( obj, time ){

$(document.body).animate({scrollTop:$(obj).offset().top}, time );

}

//平滑滚动到某元素中部

function _scrollMiddle( obj, time ){

$(document.body).animate({scrollTop:$(obj).offset().top + $(selector).height()/2 - $(window).height()/2}, time );

}

//=================
// 说明 ：用 Javascript 实现锚点(Anchor)间平滑跳转 
// 来源 ：ThickBox 2.1 
// 整理 ：Yanfu Xie [xieyanfu@yahoo.com.cn] 
// 日期 ：07.01.17 
// 转换为数字 
var lastTimer = undefined;
function intval(v) 
{ 
	v = parseInt(v); 
	return isNaN(v) ? 0 : v; 
} 
// 获取元素信息 
function getPos(e) 
{ 
	var l = 0; 
	var t = 0; 
	var w = intval(e.style.width); 
	var h = intval(e.style.height); 
	var wb = e.offsetWidth; 
	var hb = e.offsetHeight; 
	while (e.offsetParent){ 
		l += e.offsetLeft + (e.currentStyle?intval(e.currentStyle.borderLeftWidth):0); 
		t += e.offsetTop + (e.currentStyle?intval(e.currentStyle.borderTopWidth):0); 
		e = e.offsetParent; 
	} 
	l += e.offsetLeft + (e.currentStyle?intval(e.currentStyle.borderLeftWidth):0); 
	t += e.offsetTop + (e.currentStyle?intval(e.currentStyle.borderTopWidth):0); 
	return {x:l, y:t, w:w, h:h, wb:wb, hb:hb}; 
} 
// 获取滚动条信息 
function getScroll() 
{ 
	var t, l, w, h; 
	if (document.documentElement && document.documentElement.scrollTop) { 
		t = document.documentElement.scrollTop; 
		l = document.documentElement.scrollLeft; 
		w = document.documentElement.scrollWidth; 
		h = document.documentElement.scrollHeight; 
	} else if (document.body) { 
		t = document.body.scrollTop; 
		l = document.body.scrollLeft; 
		w = document.body.scrollWidth; 
		h = document.body.scrollHeight; 
	} 
	return { t: t, l: l, w: w, h: h }; 
} 
// 锚点(Anchor)间平滑跳转 
function scroller(el, duration) 
{ 
	if(undefined != lastTimer){
		window.clearInterval(lastTimer);
		lastTimer = undefined;
	}
	if(typeof el != 'object') { el = document.getElementById(el); } 
	if(!el) return; 
	var z = this; 
	z.el = el; 
	z.p = getPos(el); 
	z.s = getScroll(); 
	z.clear = function(){window.clearInterval(z.timer);lastTimer=(z.timer=null);}; 
	z.t=(new Date).getTime(); 
	z.step = function(){ 
		var t = (new Date).getTime(); 
		var p = (t - z.t) / duration; 
		if (t >= duration + z.t) { 
			z.clear(); 
			window.setTimeout(function(){z.scroll(z.p.y, z.p.x)},13); 
		} else { 
			st = ((-Math.cos(p*Math.PI)/2) + 0.5) * (z.p.y-z.s.t) + z.s.t; 
			sl = ((-Math.cos(p*Math.PI)/2) + 0.5) * (z.p.x-z.s.l) + z.s.l; 
			z.scroll(st, sl); 
		} 
	}; 
	z.scroll = function (t, l){window.scrollTo(l, t)}; 
	lastTimer = ( z.timer = window.setInterval(function(){z.step();},13) ); 
} 